1. Field of the Invention
The present invention relates to a dispenser pump, particularly a miniature, finger-actuated, dispenser pump for atomizing perfumes, colognes or other personal care products from small containers.
2. Description of the Prior Art
This invention is an improvement to the accumulative pressure pump disclosed in U.S. Pat. No. 4,278,189.
In recent years, there has been an increase in demand for small-size, finger-actuated pump dispensers, particularly for use in atomizing colognes, perfumes and other personal care products from small, hand-held containers. Generally, these containers are preferably glass to assure the purity of the perfume, cologne or other products. An additional advantage of glass containers for colognes or perfumes is to permit the visual determination of the level of the product remaining in the container. Also, glass containers permit art decorations to be applied thereto to make aesthetically pleasing packages. Prior to the recent demand for small, miniature finger pumps, these types of cologne and perfume dispensers were generally glass bottles having a plastic coating which were pressurized with chloro-fluoro hydrocarbon propellants and utilized conventional aerosol valves for dispensing the product. However, present Federal regulations prohibit the use of chloro-fluoro hydrocarbon propellants in dispensing packages. Most aerosol packaging producers are presently utilizing aliphatic hydrocarbon propellants. However, these propellants have not been acceptable to the perfume and cologne packagers because of their odor.
Early attempts to adapt conventional, single-piston, large-size, finger-actuated pump dispensers to the small cologne or perfume containers did not prove too successful. When the conventional, large-size pumps were miniaturized, they did not provide good atomization of the perfume or cologne composition--normally prepared utilizing an alcohol or a water-alcohol base formulation. These pumps dribbled, i.e., did not atomize the perfume or cologne in sufficiently desirable small particle sizes to be effective, particularly at the beginning and end of the pump stroke.
The problem of instant atomization and the production of the desired particle size in the spray has been achieved by the double cylinder-double piston pumps, sometimes known as accumulative pressure pumps, which are currently available. Such pumps have a dual-diameter pump chamber or body, generally the upper portion being a larger diameter than the lower portion. Separate pistons are provided in each of the different diameter portions, which pistons move together on downstroke and produce accumulation of pressure in the two chambers resulting in disengagement of the outlet valve whereby fluid is expressed through the atomizer nozzle at an instantaneously high pressure to produce fine atomization from the start of the spray until the end thereof. Accumulative pressure pumps having interconnected, different diameter pump chambers or bodies are shown in U.S. Pat. Nos. Re. 28,366; 3,908,870; 3,923,250; 4,017,031; and 4,051,983.
The problem common to the miniaturized, double-piston, double-cylinder-type pumps is the difficulty in expressing the air from the dual cylinders or tank when priming the pump. Generally, these types of miniaturized pumps have very small dimensions and thus relatively small movement of their pistons to express air from the dual chamber or tank upon initial or secondary priming of the pump. One method for achieving the egress of air on priming a finger pump is shown in U.S. Pat. No. 3,774,849 which discloses the provision of either ribs or recesses on the inner wall of the pump chamber whereby the piston skirt is flexed to permit expression of air on the downstroke by the edge of the piston and allowing its exit through the atmospheric vent hole normally provided in the upper end of the pump chamber. This type of priming assistance is utilized in the sprayer shown in U.S. Pat. No. 4,051,983. However, the air is not vented through the normal side hole provided for entrance of atmospheric pressure to the container, but, rather, through the dip tube which is attached to the lower end of the lower, smaller diameter pump chamber. Thus, this results in having to force any liquid out of the dip tube in order to expell the air in the cylinder to achieve priming of the pump. Such an arrangement would appear to require an increased number of priming strokes in order to achieve full prime for the pump.
As indicated before, a problem in adapting miniaturized finger pumps for utilization in dispensers for perfumes and colognes is the difficulty in removing the last amount of liquid in the bottom of the dispenser since normally the dip tube does not extend into the lowermost point of the container and also is generally in a fixed position once the pump is installed on the container. Pressurized containers having dip tubes which are located adjacent the lowermost part of the container are shown in U.S. Pat. Nos. 1,941,898 and 2,995,278. However, these containers have the location of their dip tubes fixed due to the nature of their outlet valves.
One solution for obtaining the final amount of product in an aerosol container is shown in U.S. Pat. No. 3,191,817 wherein the dip tube is reciprocal to make contact with the flat bottom of the container.
Since most perfumes are packaged in glass containers, it is extremely difficult to precisely determine the length of a dip tube for a pump so that the dip tube will reach to the lowermost part of the container, generally that peripheral portion of the container wherein the sidewall joins the bottom since most glass containers have a crowned or convex upper surface to their bottom. Small glass containers are manufactured with quite wide tolerances for the distance between the uppermost point of the upper surface of the bottom of the container and the lip on the neck of the container. This dimension is critical in cutting and sizing the dip tube for miniaturized pumps so that the tube can extend as close to the bottom of the container as possible and yet not so contact the bottom that it restricts the entry into the tube when the end is square cut.
U.S. Pat. No. 3,840,157 discloses a hand-operated, trigger spray pump adapted for dispensing products such as household detergents or sprays or cleaners which are generally packaged in an opaque plastic bottle. This pump utilizes a reciprocating vertical plunger which has the dip tube attached to the bottom end thereof so that it moves up and down as the pump is actuated. However, the dip tubes in these types of pumps are generally cut sufficiently short so that, even upon full extension, the dip tube does not contact the bottom of the container since the tubes are relatively stiff and are thus prone to blockage if allowed to contact the bottom surface of the container. Additionally, the products are generally of a far less expensive nature than colognes or perfumes, and the consumer does not have the incentive to utilize the last few ounces of product remaining in the container.
Thus, it can be seen that there is a need in the miniature atomizing pump art to provide a pump atomizer particularly suited for perfumes, colognes and personal products which are generally expensive which will permit the dip tube to extend into the lowermost portion of the container, generally that peripheral portion of the container defined by the intersection of the sidewalls and the bottom of the container. Such a pump will permit the extraction of the maximum amount of the contents of the container.
While the pump disclosed in U.S. Pat. No. 4,278,189 overcame many of the disadvantages of the foregoing prior art pumps, further improvement in this pump was desirable. This pump, and other pumps of the type disclosed in U.S. Pat. No. 4,051,983 vent the liquid remaining between the upper and the lower pistons into the container when the lower piston skirt is deflected at the bottom of stroke. Thus, there is a need for an accumulative pressure pump that will retain the major portion of the fluid between the upper and lower pistons when the pump is at the bottom of the stroke.